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Two types of organic-inorganic hybrid structure-related lanthanide (Ln)-included selenotungstates (Ln-SeTs) [H 2 N(CH 3 ) 2 ] 11 Na 7 [Ce 4 (H 2 PTCA) 2 (H 2 O) 12 (HICA)] 2 [SeW 4 O 17 ] 2 [W 2 O 5 ] 4 [SeW 9 O 33 ] 4 ·64H 2 O ( 1 , H 3 PTCA = 1,2,3-propanetricarboxylic acid, H 2 ICA = itaconic acid) and [H 2 N(CH 3 ) 2 ] 6 Na 4 [Ln 4 SeW 8 (H 2 O) 14 (H 2 PTCA) 2 O 28 ] [SeW 9 O 33 ] 2 ·31H 2 O [Ln = Pr 3+ ( 2 ), Nd 3+ ( 3 )] were obtained by Ln nature control. The primary frameworks of 1 - 3 are composed of trivacant Keggin-type [B-α-SeW 9 O 33 ] 8- and [SeW 4 O m ] n- [Ln = Ce 3+ ( 1 ), m = 17, n = 6; Ln = Pr 3+ ( 2 ), Nd 3+ ( 3 ), m = 18, n = 8] fragments bridged by organic ligands and Ln clusters. Intriguingly, Ln nature results in the degradation of hexameric 1 to trimeric 2 - 3 . Besides, 1 @DMDSA and 3 @DMDSA composites (DMDSA·Cl = dimethyl distearylammonium chloride) were prepared through the cation exchange method, which were then reorganized to form two-dimensional (2D) honeycomb thin films by the breath figure method. Using these honeycomb thin films as electrode materials, the aptasensors were further established by utilizing methylene blue as an indicator and cDNA and Au nanoparticles as signal amplifiers to enhance the response signal so as to realize the purpose of ochratoxin A (OTA) detection. This work provides a new platform for detecting OTA and explores the application potential of POM-based composites in biological and clinical analyses.

The construction of efficient and superior nanostructured materials for the precise determination of contaminants that are hazardous to the environment has gained significant attention by the scientific community. In this regard, we fabricated a nanocomposite consisting of praseodymium vanadate (PrVO 4 ; PrV) anchored to sulfur-doped carbon nitride (PrV/SCN) and applied it to the electrochemical detection of the antibiotic drug metronidazole (MTZ). The structural and crystalline features of the as-prepared PrV/SCN nanocomposite were characterized by various analytical and spectroscopic methods. More distinctly, the PrV/SCN nanocomposite-modified glassy carbon electrode (GCE) exhibits an outstanding linear range (0.001-2444 μM), high sensitivity (1.386 μA/μM cm 2 ), low detection limit (0.8 nM), good reproducibility, and strong anti-interference ability. Notably, the PrV/SCN sensor can determine MTZ in spiked urine and water samples with high recoveries, suggesting its feasibility for real-time applications. Our findings establish PrV/SCN as a robust and promising platform for electrochemical detection. This promotes innovative design for the synthesis of novel functional nanocomposites.

Ceria nanocubes (NC) modified with increasing concentrations of praseodymium (5, 10, 15, and 20 mol %) have been successfully synthesized by a hydrothermal method. The as-synthesized Pr-modified ceria nanocubes exhibit an enhanced oxidase-like activity on the organic dye TMB within a wide range of concentrations and durations. The oxidase activity increases with increasing Pr amounts in Pr-modified ceria nanocubes within the investigated concentration range. Meanwhile, these Pr-modified ceria nanocubes also show higher reducibility than pure ceria nanocubes. The kinetics of their oxidase mimetic activity is fitted with the Michaelis-Menten equation. A mechanism has been proposed on how the Pr incorporation could affect the energy level of the bands in ceria and hence facilitate the TMB oxidation reaction. The presence of Pr 3+ species on the surface also contributes to the increasing activity of the Pr-modified ceria nanocubes present higher oxidase activity than pure ceria nanocubes.